
import math
def dot(a,b):
   sum=0;
   c=zip(a,b)
   for item in c:
       sum+=item[0]*item[1]

       return sum

def mo(a):
       sum=0
       for i in a:
           sum+=i*i
       return sum**0.5


def angle(a,b):
    ji=dot(a,b)
    amo=mo(a)
    bmo=mo(b)
    cos=ji/(amo*bmo)
    hudu=math.acos(cos)
    jiaodu=hudu*180/math.pi
    return jiaodu
